Module traits tracking issue

[LPTK]

Required changes

• [ ] Make "require captures" use the same instance (see CapturingTraitImpls.mls)

Features to add support for:

• [ ] Add using clauses as an alternative to require that does not request a unique instance

Tests/use cases to add to the test suite:

• [ ] A parser with mutually-recursive functions
  • [ ] from different trait: would probably cause cycle error;
  • [ ] from the same trait: can we still do partial implementations?